A simplified CaO-V_(2)O_(5)-MnO_(2) system was established to qualitatively and quantitatively investigate the transformation behavior of vanadates.The results demonstrated dynamic transformations between calcium vana...A simplified CaO-V_(2)O_(5)-MnO_(2) system was established to qualitatively and quantitatively investigate the transformation behavior of vanadates.The results demonstrated dynamic transformations between calcium vanadate and manganese vanadate as n(CaO)/n(V_(2)O_(5))/n(MnO_(2))ratios and roasting temperatures varied.When MnO_(2) was incrementally added with n(CaO)/n(V_(2)O_(5))of 2,some Ca_(2)V_(2)O_(7) converted to Mn_(2)V_(2)O_(7).The mass of vanadium as calcium vanadate consistently exceeded that as manganese vanadate.Conversely,when CaO was gradually added with n(MnO_(2))/n(V_(2)O_(5))of 2,Mn_(2)V_(2)O_(7) tended to transform into Ca_(2)V_(2)O_(7) and Ca3V2O8.The affinity of vanadium for calcium was higher compared that of vanadium for manganese.The specific type of calcium vanadate formed depended on both n(CaO)/n(V_(2)O_(5))/n(MnO_(2))values and roasting temperatures,while manganese vanadate remained predominantly as Mn_(2)V_(2)O_(7).The influence of roasting temperature on the conversion between calcium vanadate and manganese vanadate was minimal.At n(CaO)/n(V_(2)O_(5))/n(MnO_(2))of 2/1/2 and temperatures ranging from 650 to 850°C,the mass ratio of vanadium present as calcium vanadate to manganese vanadate stabilized at approximately 2.展开更多
Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kineti...Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kinetics still require improvement.Encouraged by the excellent electrochemical performance of titanium-based anode materials,here,we present a novel titanium vanadate@carbon(TVO@C)material as anode for SIBs.Our TVO@C material is synthesized via a facile coprecipitation method,with the following annealing process in an acetylene atomosphere.The opened ion channel and the oxygen vacancies within TVO@C facilitate the diffusion of Na^(+) ions,reducing their diffusion barrier.Thus,an ultrahigh rate of 100 A g^(-1)and long life of 10,000 cycles have been achieved.Furthermore,the TVO@C electrode exhibits stable performance,not only at room temperature,but also at temperatures as low as 20 C.The TVO@CjjNa_(3)V_(2)(PO_(4))_(3)@C full cells have also achieved stable discharge/charge for 500 cycles.It is believed that this strategy provides new insight into the development of advanced electrodes and provides a new opportunity for constructing novel high rate electrodes.展开更多
High-performance aqueous zinc(Zn)-ion batteries(AZIBs)have emerged as one of the greatest favorable candidates for next-generation energy storage systems because of their low cost,sustainability,high safety,and eco-fr...High-performance aqueous zinc(Zn)-ion batteries(AZIBs)have emerged as one of the greatest favorable candidates for next-generation energy storage systems because of their low cost,sustainability,high safety,and eco-friendliness.In this report,we prepared magnesium vanadate(MgVO)-based nanostructures by a facile single-step solvothermal method with varying experimental reaction times(1,3,and 6 h)and investigated the effect of the reaction time on the morphology and layered structure for MgVO-based compounds.The newly prepared MgVO-1 h,MgVO-3 h and MgVO-6 h samples were used as cathode materials for AZIBs.Compared to the MgVO-1 h and MgVO-6 h cathodes,the MgVO-3 h cathode showed a higher specific capacity of 492.74 mA h g^(-1) at 1 A g^(-1) over 500 cycles and excellent rate behavior(291.58 mA h g^(-1) at 3.75 A g^(-1))with high cycling stability(116%)over 2000 cycles at 5 A g^(-1).Moreover,the MgVO-3 h electrode exhibited good electrochemical performance owing to its fast Zn-ion diffusion kinetics.Additionally,various ex-situ analyses confirmed that the MgVO-3 h cathode displayed excellent insertion/extraction of Zn^(2+)ions during charge and discharge processes.This study offers an efficient method for the synthesis of nanostructured MgVO-based cathode materials for high-performance AZIBs.展开更多
Developing fast-charging lithium-ion batteries(LIBs)that feature high energy density is critical for the scalable application of electric vehicles.Iron vanadate(FVO)holds great potential as anode material in fast-char...Developing fast-charging lithium-ion batteries(LIBs)that feature high energy density is critical for the scalable application of electric vehicles.Iron vanadate(FVO)holds great potential as anode material in fast-charging LIBs because of its high theoretical specific capacity and the high natural abundance of its constituents.However,the capacity of FVO rapidly decays due to its low electrical conductivity.Herein,uniform FVO nanoparticles are grown in situ on ordered mesoporous carbon(CMK-3)support,forming a highly electrically conductive porous network,FVO/CMK-3.The structure of CMK-3 helps prevent agglomeration of FVO particles.The electrically conductive nature of CMK-3 can further enhance the electrical conductivity of FVO/CMK-3 and buffer the volume expansion of FVO particles during cycling processes.As a result,the FVO/CMK-3 displays excellent fast-charging performance of 364.6 mAh·g^(-1)capacity for 2500 cycles at 10 A·g^(-1)(with an ultralow average capacity loss per cycle of 0.003%)through a pseudocapacitive-dominant process.Moreover,the LiCoO_(2)//FVO/CMK-3 full cell achieves a high capacity of 100.2 mAh·g^(-1)and a high capacity retention(96.2%)after 200 cycles.The superior electrochemical performance demonstrates that FVO/CMK-3 is an ideal anode material candidate for fast-charging,stable LIBs with high energy density.展开更多
The multifunctional characteristics of barium zinc vanadate(BaZnV_(2)O_(7))nanoparticles(BZV NPs)were explored in this study,focusing on their photocatalytic activity,supercapacitor performance,and sensing abilities.X...The multifunctional characteristics of barium zinc vanadate(BaZnV_(2)O_(7))nanoparticles(BZV NPs)were explored in this study,focusing on their photocatalytic activity,supercapacitor performance,and sensing abilities.X-ray diffraction analysis confirmed that the crystallites were 40.3 nm in size,whereas ultraviolet visible diffuse reflectance spectroscopy revealed an energy bandgap of 5.28 eV.Functional groups,elemental composition,and morphology were assessed using Fourier transform infrared spectroscopy,energy-dispers-ive X-ray spectroscopy,and scanning electron microscopy,respectively.The photocatalytic efficiency of the BZV NPs was evaluated at various catalyst dosages,dye concentrations,and pH levels,for the degradation of acid black-52(AB-52)dye under UV light.Cyclic voltammetry and galvanostatic charge-discharge analyses were performed to determine the energy storage and cyclic stability of the BZV-NP-modified carbon paste electrode.In addition,a novel electrochemical sensor based on BZV was developed to accurately detect the concentration of biomolecules and chemical drugs.BZV nanoparticles exhibited remarkable photocatalytic dye degradation up to 80.4%,indicating their application in waste water treatment.The BZV-NP-modified carbon paste electrode exhibited a superior specific capacit-ance of 714.15 F·g−1 with excellent cycling stability over 1000 cycles.The electrodes efficiently detected biomolecules such as ascorbic acid and uric acid,chemical drugs including paracetamol and ibuprofen,and heavy metals such as mercury,cobalt,and cadmium in the concentration range of 1-5 mM.The limit of detection(LOD)was measured for all analytes,and the electrode exhibited high sensitivity.These multifunctional properties render BZV promising material for energy storage and environmental monitoring applications.展开更多
Metal vanadates garner significant interest because of their exceptional potential for use in diverse practical applications,which stems from their unique framework structures,bond strength heterogeneities,and strong ...Metal vanadates garner significant interest because of their exceptional potential for use in diverse practical applications,which stems from their unique framework structures,bond strength heterogeneities,and strong O^(2-)-V^(5+)charge-transfer bands.However,their optoelectronic properties have not yet been sufficiently explored.In this study,we synthesized three high-purity calcium vanadate compounds(Ca V_(2)O_(6),Ca_(2)V_(2)O_(7),and Ca_(3)V_(2)O_(8))and comprehensively investigated their optoelectronic properties via first-principles calculations and experimental characterizations.Ca V_(2)O_(6),Ca_(2)V_(2)O_(7),and Ca_(3)V_(2)O_(8) are indirect band gap semiconductors with band gaps of 2.5-3.4 e V.A comparative analysis between density functional theory(DFT)and DFT+U(local Coulomb interaction,U)calculations revealed that standard DFT was sufficient to accurately describe the lattice parameters and band gaps of these vanadates.Further luminescence studies revealed significant photo-and electro-luminescence properties within the visible light spectrum.Notably,the luminescence intensity of CaV_(2)O_(6) exhibited a remarkable 10-fold enhancement under a modest pressure of only 0.88 GPa,underscoring its exceptional potential for use in pressure-tunable optical applications.These findings provide deeper insight into the electronic structures and optical behaviors of vanadates and highlight their potential as strong candidates for application in phosphor materials and optoelectronic devices.展开更多
Layered ammonium vanadate has become a promising cathode material for aqueous zinc ion batteries(ZIBs)due to its small mass and large ionic radius of ammonium ions as well as the consequent large layer spacing and hig...Layered ammonium vanadate has become a promising cathode material for aqueous zinc ion batteries(ZIBs)due to its small mass and large ionic radius of ammonium ions as well as the consequent large layer spacing and high specific capacity.However,the irreversible de-ammoniation caused by N·H···O bonds damaged would impair cycle life of ZIBs and the strong electrostatic interaction between Zn^(2+)and V-O frame could slower the mobility of Zn^(2+).Furthermore,the thermal instability of ammonium vanadate also limits the use of common carbon coating modification method to solve the problem.Herein,V_(2)CT_(X)MXene was innovatively selected as a bifunctional source to in-situ derivatized(NH_(4))_(2)V_(8)O_(20)·x H_(2)O with amorphous carbon-coated(NHVO@C)via one-step hydrothermal method in relatively moderate temperature.The amorphous carbon shell derived from the V_(2)CT_(X)MXene as a conductive framework to effectively improve the diffusion kinetics of Zn^(2+)and the robust carbon skeleton could alleviate the ammonium dissolution during long-term cycling.As a result,zinc ion batteries using NHVO@C as cathode exhibit superior electrochemical performance.Moreover,the assembled foldable or high loading(10.2 mg/cm^(2))soft-packed ZIBs further demonstrates its practical application.This study provided new insights into the development of the carbon cladding process for thermally unstable materials in moderate temperatures.展开更多
Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not y...Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not yet fully understood.In this study,the V(V)reduction mechanisms with concomitant V isotope fractionation by the Gram-positive bacterium Bacillus subtilis(B.subtilis)and the Gramnegative bacterium Thauera humireducens(T.humireducens)were investigated.Both strains could effectively reduce V(V),removing(90.5%±1.6%)and(93.0%±1.8%)of V(V)respectively from an initial concentration of 50 mg L^(-1) during a 10-day incubation period.V(V)was bioreduced to insoluble vanadium(IV),which was distributed both inside and outside the cells.Electron transfer via cytochrome C,nicotinamide adenine dinucleotide,and glutathione played critical roles in V(V)reduction.Metabolomic analysis showed that differentially enriched metabolites(quinone,biotin,and riboflavin)mediated electron transfer in both strains.The aqueous V in the remaining solution became isotopically heavier as V(V)bioreduction proceeded.The obtained V isotope composition dynamics followed a Rayleigh fractionation model,and the isotope enrichment factor(e)was(–0.54‰±0.04‰)for B.subtilis and(–0.32‰±0.03‰)for T.humireducens,with an insignificant difference.This study provides molecular insights into electron transfer for V(V)bioreduction and reveals V isotope fractionation during this bioprocess,which is helpful for understanding V biogeochemistry and developing novel strategies for V remediation.展开更多
Elemental doping of BiVO_(4) crystal lattices effectively enhances carrier separation,thereby facilitating efficient photoelectrochemical water splitting.However,the positive effect of elementally induced lattice dist...Elemental doping of BiVO_(4) crystal lattices effectively enhances carrier separation,thereby facilitating efficient photoelectrochemical water splitting.However,the positive effect of elementally induced lattice distortions on hole extraction has been neglected.Herein,the crystal lattice of BiVO_(4) is distorted by doping with an inexpensive Cs metal;then,CoFe_(2)O_(4) is used as an efficient hole-extraction layer to further modify the surface of the doped photoanode.Benefiting from the above design,the newly prepared CoFe_(2)O_(4)-Cs-BiVO_(4) photoanode achieved a photocurrent density of 5.66 mA cm^(–2) at 1.23 V vs.a reversible hydrogen electrode,indicating a 3.9-fold improvement in photocurrent density.Detailed physicochemical characterization and density functional theory calculations showed that the lattice distortion induced by Cs doping promoted the directional migration of BiVO_(4) bulk-phase holes to the CoFe_(2)O_(4) layer.Additionally,the coupled CoFe_(2)O_(4) can be used as a hole extraction layer to further enhance the interfacial migration of carriers.The synergistic effect of the two effectively promotes the directional migration of photogenerated carriers from the BiVO_(4) bulk phase to the active sites of the oxygen evolution reaction,thereby effectively inhibiting carrier recombination.This study revealed the positive effect of the dual-hole extraction strategy on solar energy conversion,thereby opening new avenues for the rational design of photoanodes.展开更多
Layered vanadates are ideal energy storage materials due to their multielectron redox reactions and excellent cation storage capacity.However,their practical application still faces challenges,such as slow reaction ki...Layered vanadates are ideal energy storage materials due to their multielectron redox reactions and excellent cation storage capacity.However,their practical application still faces challenges,such as slow reaction kinetics and poor structural stability.In this study,we synthesized[Me_(2)NH_(2)]V_(3)O_(7)(MNVO),a layered vanadate with expended layer spacing and enhanced pH resistance,using a one-step simple hydrothermal gram-scale method.Experimental analyses and density functional theory(DFT)calculations revealed supportive ionic and hydrogen bonding interactions between the thin-layered[Me_(2)NH_(2)]+cation and[V_(3)O_(7)]-anion layers,clarifying the energy storage mechanism of the H^(+)/Zn^(2+)co-insertion.The synergistic effect of these bonds and oxygen vacancies increased the electronic conductivity and significantly reduced the diffusion energy barrier of the insertion ions,thereby improving the rate capability of the material.In an acidic electrolyte,aqueous zinc-ion batteries employing MNVO as the cathode exhibited a high specific capacity of 433 mAh g^(-1)at 0.1 A g^(-1).The prepared electrodes exhibited a maximum specific capacity of 237 mAh g^(-1)at 5 A g^(-1)and maintained a capacity retention of 83.5%after 10,000 cycles.This work introduces a novel approach for advancing layered cathodes,paving the way for their practical application in energy storage devices.展开更多
The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadi...The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.展开更多
A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium c...A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium chromate from CVR in sodium bicarbonate solution.Results indicate that the stability of calcium vanadate and calcium chromate depends on pH and[HCO3?].CaV2O6?4H2O transforms into CaV2O6?4H2O,CaV2O6?2H2O,CaV2O6,Ca2V2O7?2H2O,and Ca5(VO4)3(OH)when pH increases from 7.51 to 12.32.Increasing pH and reducing CVR dosage improve the vanadate extraction rate,and high V2O5 and Na2Cr2O7?2H2O extraction rates are achieved in dilute NaHCO3 solution.Moreover,addition of NaOH positively contributes to the recovery of vanadate and chromate from CVR.Over 95%V2O5 and Na2Cr2O7?2H2O in CVR can be extracted from 60 g/L NaHCO3 and 30 g/L NaOH solutions at 90°C for 2 h.In order to reduce the hazardous residue containing chromate after recovery of CVR,calcium circulation is presented.Results show that more than 60%lime can be saved with fresh residue addition to remove vanadate from sodium chromate solution due to the active CaCO3.Moreover,no lime is required in removal of vanadate when the roasting residue is added.Therefore,a novel process is developed for utilization of CVR.展开更多
The number of papers about decavanadate has doubled in the past decade. In the present review, new insights into decavanadate biochemistry, cell biology, and antidiabetic and antitumor activities are described. Decame...The number of papers about decavanadate has doubled in the past decade. In the present review, new insights into decavanadate biochemistry, cell biology, and antidiabetic and antitumor activities are described. Decameric vanadate species (V10) clearly differs from monomeric vanadate (V1), and affects differently calcium pumps, and structure and function of myosin and actin. Only decavanadate inhibits calcium accumulation by calcium pump ATPase, and strongly inhibits actomyosin ATPase activity (IC50 = 1.4 μmol/L, V10), whereas no such ef- fects are detected with V1 up to 150 μmol/L; prevents actin polymerization (IC50 of 68 μmol/L, whereas no effects detected with up to 2 mmol/L V1); and interacts with actin in a way that induces cysteine oxidation and vanadate reduction to vanadyl. Moreover, in vivo decavanadate toxicity studies have revealed that acute exposure to polyoxovanadate induces different changes in antioxidant enzymes and oxidative stress parameters, in comparison with vanadate. In vitro studies have clearly demonstrated that mitochondrial oxygen consumption is strongly affected by decavanadate (IC50, 0.1 μmol/L); perhaps the most relevant biological effect. Finally, decavanadate (100 μmol/L) increases rat adipocyte glucose accumulation more potently than several vanadium complexes. Preliminary studies sug- gest that decavanadate does not have similar effects in human adipocytes. Although decavanadate can be a useful biochemical tool, further studies must be carried out before it can be conf irmed that decavanadate and its complexes can be used as anticancer or antidiabetic agents.展开更多
Mg/Al-CO3 layered double hydroxide （LDH2） with Mg（II）：Al（III） molar ratio of 2：1 was synthesized by co-precipitation method and its calcined product Mg2Al-CLDH（CLDH2） was prepared by heating Mg2Al-LDH at 773...Mg/Al-CO3 layered double hydroxide （LDH2） with Mg（II）：Al（III） molar ratio of 2：1 was synthesized by co-precipitation method and its calcined product Mg2Al-CLDH（CLDH2） was prepared by heating Mg2Al-LDH at 773 K for 6 h. Removal of vanadate anion （ 3-4VO ） from aqueous solution on CLDH2 was studied. Batch studies were carried out to address various experimental parameters such as Mg/Al molar ratio, adsorbent dosage, initial concentration of solution, contact time and temperature. Vanadate was removed effectively at the optimized experimental conditions. The adsorption kinetics data fitted the pseudo-first-order model. Isotherms for adsorption vanadate by CLDH2 at different solution temperatures were well described using the Langmuir and Freundlich equations, and the isotherm parameters were calculated using linear regression analysis. The adsorption data fitted the langmuir model with good values of the correlation coefficient （R2〉0.999）. The negative value ofΔGΘand the positive value ofΔHΘindicate that the adsorption processes are spontaneous endothermic in nature. The mechanism of adsorption suggests that the surface adsorption is the main process.展开更多
Rechargeable aqueous zinc-ion batteries(AZIBs)have their unique advantages of cost efficiency,high safety,and environmental friendliness.However,challenges facing the cathode materials include whether they can remain ...Rechargeable aqueous zinc-ion batteries(AZIBs)have their unique advantages of cost efficiency,high safety,and environmental friendliness.However,challenges facing the cathode materials include whether they can remain chemically stable in aqueous electrolyte and provide a robust structure for the storage of Zn2+.Here,we report on H11Al2V6O23.2@graphene(HAVO@G)with exceptionally large layer spacing of(001)plane(13.36?).The graphene-wrapped structure can keep the structure stable during discharge/charge process,thereby promoting the inhibition of the dissolution of elements in the aqueous electrolyte.While used as cathode for AZIBs,HAVO@G electrode delivers ideal rate performance(reversible capacity of 305.4,276.6,230.0,201.7,180.6 mAh g?1 at current densities between 1 and 10 A g?1).Remarkably,the electrode exhibits excellent and stable cycling stability even at a high loading mass of^15.7 mg cm?2,with an ideal reversible capacity of 131.7 mAh g?1 after 400 cycles at 2 A g?1.展开更多
Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniqu...Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100°C with poly（vinyl pyrrolidone） （PVP） and urea （pH = 2） and at 160°C with NaHCO3 （pH = 7 and 8）, respectively. The PVP-derived BiVO4 showed much higher surface areas （5.0-8.4 m2/g） and narrower bandgap energies （2.45-2.49 eV）. The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.展开更多
Aqueous rechargeable zinc-ion battery(ZIB)is considered to be a potential energy storage system for large-scale applications due to its environmental friendliness,high safety,and low cost.However,it remains challengin...Aqueous rechargeable zinc-ion battery(ZIB)is considered to be a potential energy storage system for large-scale applications due to its environmental friendliness,high safety,and low cost.However,it remains challenging to develop suitable cathode materials with high specific capacity and long-term cyclic stability.Herein,we have fabricated freestanding Sr0.19V2O51.3H2O/carbon nanotubes(SrVO/CNTs)composite films with different mass ratios by incorporating SrVO into CNTs network.The synthesized SrVO possesses a large interlayer spacing of 1.31 nm,which facilitates Zn(2+)diffusion.Furthermore,the SrVO/CNTs composite film with conductive network structure promotes electron transfer and ensures good contact between SrVO and CNTs during the long-term cycling process.As a result,the battery based on the SrVO/CNTs composite cathode with a mass ratio of 7:3 delivers a specific capacity of 326 mAh·g^(-1)at 0.1 A·g^(-1)and 145 mAh·g^(-1)at 5 A·g^(-1),demonstrating a high capacity and excellent rate capability.Remarkably,the assembled ZIB shows good capacity retention of 91%even after ultra-long cycling for 7500 cycles at a high current rate of 5 Ag^(-1).More importantly,the battery also delivers a high energy density and power density,as 290 Wh·kg^(-1)at 125 W·kg^(-1)(0.1 A·g^(-1)),or 115 Wh·kg^(-1)at 6078 W·kg^(-1)(5 Ag^(-1)).The results demonstrate that the SrVO/CNTs composite is a promising cathode toward large-scale energy storage applications.展开更多
Ammonium vanadate with bronze structure(NH_(4)V_(4)O_(10))is a promising cathode material for zinc-ion batteries due to its high specific capacity and low cost.However,the extraction of NH^(+)_(4) at a high voltage du...Ammonium vanadate with bronze structure(NH_(4)V_(4)O_(10))is a promising cathode material for zinc-ion batteries due to its high specific capacity and low cost.However,the extraction of NH^(+)_(4) at a high voltage during charge/discharge processes leads to irreversible reaction and structure degradation.In this work,partial NH^(+)_(4) ions were pre-removed from NH_(4)V_(4)O_(10) through heat treatment;NH_(4)V_(4)O_(10) nanosheets were directly grown on carbon cloth through hydrothermal method.Defi-cient NH_(4)V_(4)O_(10)(denoted as NVO),with enlarged interlayer spacing,facilitated fast zinc ions transport and high storage capacity and ensured the highly reversible electrochemical reaction and the good stability of layered structure.The NVO nanosheets delivered a high specific capac-ity of 457 mAh g^(−1) at a current density of 100 mA g^(−1) and a capacity retention of 81%over 1000 cycles at 2 A g^(−1).The initial Coulombic efficiency of NVO could reach up to 97%compared to 85%of NH_(4)V_(4)O_(10) and maintain almost 100%during cycling,indicating the high reaction reversibility in NVO electrode.展开更多
It is urgent to develop high-performance cathode materials for the emerging aqueous zinc-ion batteries with a facile strategy and optimize the related components.Herein,a Ca0.23V2O5·0.95 H2O nanobelt cathode mate...It is urgent to develop high-performance cathode materials for the emerging aqueous zinc-ion batteries with a facile strategy and optimize the related components.Herein,a Ca0.23V2O5·0.95 H2O nanobelt cathode material with a rather large interlayer spacing of 13.0 A is prepared via a one-step hydrothermal approach.The battery with this cathode material and 3 M Zn(CF3SO3)2 electrolyte displays high specific capacity(355.2 mAh g^(-1)at 0.2 A g^(-1)),great rate capability(240.8 mAh g^(-1)at 5 A g^(-1)),and excellent cyclability(97.7%capacity retention over 2000 cycles).Such superior performances are ascribed to fast electrochemical kinetics,outstanding electrode/electrolyte interface stability,and nearly dendrite-free characteristic.Instead,when ZnSO4 or Zn(ClO4)2 is used to replace Zn(CF3SO3)2,the electrochemical performances become much inferior,due to the slow electrochemical kinetics,inhomogeneous Zn stripping/plating process,and the formation of large dendrites and byproducts.This work not only discloses a high-performance cathode material for aqueous zinc-ion batteries but also offers a reference for the choice of electrolyte salt.展开更多
Due to the intrinsic advantages of nontoxicity, low-cost, and abundant resource of metallic zinc, aqueous zinc-ion batteries (ZIBs) have attracted universal interest [1,2]. Tremendous cathode materials have been explo...Due to the intrinsic advantages of nontoxicity, low-cost, and abundant resource of metallic zinc, aqueous zinc-ion batteries (ZIBs) have attracted universal interest [1,2]. Tremendous cathode materials have been exploited in aqueous ZIBs, such as manganese-based materials [3-11], Co-based materials [12,13] and vanadium-based materials [14-21].展开更多
基金finally supported by the National Natural Science Foundation of China (Nos.52204309,52174277,52374300)。
文摘A simplified CaO-V_(2)O_(5)-MnO_(2) system was established to qualitatively and quantitatively investigate the transformation behavior of vanadates.The results demonstrated dynamic transformations between calcium vanadate and manganese vanadate as n(CaO)/n(V_(2)O_(5))/n(MnO_(2))ratios and roasting temperatures varied.When MnO_(2) was incrementally added with n(CaO)/n(V_(2)O_(5))of 2,some Ca_(2)V_(2)O_(7) converted to Mn_(2)V_(2)O_(7).The mass of vanadium as calcium vanadate consistently exceeded that as manganese vanadate.Conversely,when CaO was gradually added with n(MnO_(2))/n(V_(2)O_(5))of 2,Mn_(2)V_(2)O_(7) tended to transform into Ca_(2)V_(2)O_(7) and Ca3V2O8.The affinity of vanadium for calcium was higher compared that of vanadium for manganese.The specific type of calcium vanadate formed depended on both n(CaO)/n(V_(2)O_(5))/n(MnO_(2))values and roasting temperatures,while manganese vanadate remained predominantly as Mn_(2)V_(2)O_(7).The influence of roasting temperature on the conversion between calcium vanadate and manganese vanadate was minimal.At n(CaO)/n(V_(2)O_(5))/n(MnO_(2))of 2/1/2 and temperatures ranging from 650 to 850°C,the mass ratio of vanadium present as calcium vanadate to manganese vanadate stabilized at approximately 2.
基金supported by National Nature Science Foundation of China(22105118)Nature Science Foundation of Shandong Provinces(ZR2021QB095)China Postdoctoral Science Foundation(2020TQ0183 and 2021M701979).
文摘Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kinetics still require improvement.Encouraged by the excellent electrochemical performance of titanium-based anode materials,here,we present a novel titanium vanadate@carbon(TVO@C)material as anode for SIBs.Our TVO@C material is synthesized via a facile coprecipitation method,with the following annealing process in an acetylene atomosphere.The opened ion channel and the oxygen vacancies within TVO@C facilitate the diffusion of Na^(+) ions,reducing their diffusion barrier.Thus,an ultrahigh rate of 100 A g^(-1)and long life of 10,000 cycles have been achieved.Furthermore,the TVO@C electrode exhibits stable performance,not only at room temperature,but also at temperatures as low as 20 C.The TVO@CjjNa_(3)V_(2)(PO_(4))_(3)@C full cells have also achieved stable discharge/charge for 500 cycles.It is believed that this strategy provides new insight into the development of advanced electrodes and provides a new opportunity for constructing novel high rate electrodes.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIP)(No.2018R1A6A1A03025708).
文摘High-performance aqueous zinc(Zn)-ion batteries(AZIBs)have emerged as one of the greatest favorable candidates for next-generation energy storage systems because of their low cost,sustainability,high safety,and eco-friendliness.In this report,we prepared magnesium vanadate(MgVO)-based nanostructures by a facile single-step solvothermal method with varying experimental reaction times(1,3,and 6 h)and investigated the effect of the reaction time on the morphology and layered structure for MgVO-based compounds.The newly prepared MgVO-1 h,MgVO-3 h and MgVO-6 h samples were used as cathode materials for AZIBs.Compared to the MgVO-1 h and MgVO-6 h cathodes,the MgVO-3 h cathode showed a higher specific capacity of 492.74 mA h g^(-1) at 1 A g^(-1) over 500 cycles and excellent rate behavior(291.58 mA h g^(-1) at 3.75 A g^(-1))with high cycling stability(116%)over 2000 cycles at 5 A g^(-1).Moreover,the MgVO-3 h electrode exhibited good electrochemical performance owing to its fast Zn-ion diffusion kinetics.Additionally,various ex-situ analyses confirmed that the MgVO-3 h cathode displayed excellent insertion/extraction of Zn^(2+)ions during charge and discharge processes.This study offers an efficient method for the synthesis of nanostructured MgVO-based cathode materials for high-performance AZIBs.
基金supported by the National Natural Science Foundation of China(No.52002170)the Central Guidance Fund Project for Local Scientific and Technological Development in Qinghai Province(No.2024ZY013)+1 种基金the Foundation of Key Laboratory of Flexible Electronics of Zhejiang Province(No.2023FE011)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX24_1635).
文摘Developing fast-charging lithium-ion batteries(LIBs)that feature high energy density is critical for the scalable application of electric vehicles.Iron vanadate(FVO)holds great potential as anode material in fast-charging LIBs because of its high theoretical specific capacity and the high natural abundance of its constituents.However,the capacity of FVO rapidly decays due to its low electrical conductivity.Herein,uniform FVO nanoparticles are grown in situ on ordered mesoporous carbon(CMK-3)support,forming a highly electrically conductive porous network,FVO/CMK-3.The structure of CMK-3 helps prevent agglomeration of FVO particles.The electrically conductive nature of CMK-3 can further enhance the electrical conductivity of FVO/CMK-3 and buffer the volume expansion of FVO particles during cycling processes.As a result,the FVO/CMK-3 displays excellent fast-charging performance of 364.6 mAh·g^(-1)capacity for 2500 cycles at 10 A·g^(-1)(with an ultralow average capacity loss per cycle of 0.003%)through a pseudocapacitive-dominant process.Moreover,the LiCoO_(2)//FVO/CMK-3 full cell achieves a high capacity of 100.2 mAh·g^(-1)and a high capacity retention(96.2%)after 200 cycles.The superior electrochemical performance demonstrates that FVO/CMK-3 is an ideal anode material candidate for fast-charging,stable LIBs with high energy density.
基金fund provided by the Ongoing Research Funding program-Research Chairs(No.ORF-RC-2025-1609),King Saud University,Riyadh,Saudi Arabia.
文摘The multifunctional characteristics of barium zinc vanadate(BaZnV_(2)O_(7))nanoparticles(BZV NPs)were explored in this study,focusing on their photocatalytic activity,supercapacitor performance,and sensing abilities.X-ray diffraction analysis confirmed that the crystallites were 40.3 nm in size,whereas ultraviolet visible diffuse reflectance spectroscopy revealed an energy bandgap of 5.28 eV.Functional groups,elemental composition,and morphology were assessed using Fourier transform infrared spectroscopy,energy-dispers-ive X-ray spectroscopy,and scanning electron microscopy,respectively.The photocatalytic efficiency of the BZV NPs was evaluated at various catalyst dosages,dye concentrations,and pH levels,for the degradation of acid black-52(AB-52)dye under UV light.Cyclic voltammetry and galvanostatic charge-discharge analyses were performed to determine the energy storage and cyclic stability of the BZV-NP-modified carbon paste electrode.In addition,a novel electrochemical sensor based on BZV was developed to accurately detect the concentration of biomolecules and chemical drugs.BZV nanoparticles exhibited remarkable photocatalytic dye degradation up to 80.4%,indicating their application in waste water treatment.The BZV-NP-modified carbon paste electrode exhibited a superior specific capacit-ance of 714.15 F·g−1 with excellent cycling stability over 1000 cycles.The electrodes efficiently detected biomolecules such as ascorbic acid and uric acid,chemical drugs including paracetamol and ibuprofen,and heavy metals such as mercury,cobalt,and cadmium in the concentration range of 1-5 mM.The limit of detection(LOD)was measured for all analytes,and the electrode exhibited high sensitivity.These multifunctional properties render BZV promising material for energy storage and environmental monitoring applications.
基金supported by the National Natural Science Foundation of China(Nos.12404045 and 52371148)the National Key R&D Program of China(No.2018YFC 1900500)+1 种基金the Foundation of Chongqing Normal University,China(No.23XLB015)the Science and Technology Research Program of Chongqing Municipal Education Commission,China(No.KJQN-202400553)。
文摘Metal vanadates garner significant interest because of their exceptional potential for use in diverse practical applications,which stems from their unique framework structures,bond strength heterogeneities,and strong O^(2-)-V^(5+)charge-transfer bands.However,their optoelectronic properties have not yet been sufficiently explored.In this study,we synthesized three high-purity calcium vanadate compounds(Ca V_(2)O_(6),Ca_(2)V_(2)O_(7),and Ca_(3)V_(2)O_(8))and comprehensively investigated their optoelectronic properties via first-principles calculations and experimental characterizations.Ca V_(2)O_(6),Ca_(2)V_(2)O_(7),and Ca_(3)V_(2)O_(8) are indirect band gap semiconductors with band gaps of 2.5-3.4 e V.A comparative analysis between density functional theory(DFT)and DFT+U(local Coulomb interaction,U)calculations revealed that standard DFT was sufficient to accurately describe the lattice parameters and band gaps of these vanadates.Further luminescence studies revealed significant photo-and electro-luminescence properties within the visible light spectrum.Notably,the luminescence intensity of CaV_(2)O_(6) exhibited a remarkable 10-fold enhancement under a modest pressure of only 0.88 GPa,underscoring its exceptional potential for use in pressure-tunable optical applications.These findings provide deeper insight into the electronic structures and optical behaviors of vanadates and highlight their potential as strong candidates for application in phosphor materials and optoelectronic devices.
基金financially supported by the National Natural Science Foundation of China(Nos.52402271,22005167 and52302273)the Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province(No.2024KJH129)+2 种基金the Taishan Scholar Project of Shandong Provinceof China(Nos.tsqn202211160,tsqn202312199)Shandong Provincial Natural Science Foundation of China(Nos.ZR2022QE003 and ZR2023QE176)China Postdoctoral Science Foundation(No.2023M741810)。
文摘Layered ammonium vanadate has become a promising cathode material for aqueous zinc ion batteries(ZIBs)due to its small mass and large ionic radius of ammonium ions as well as the consequent large layer spacing and high specific capacity.However,the irreversible de-ammoniation caused by N·H···O bonds damaged would impair cycle life of ZIBs and the strong electrostatic interaction between Zn^(2+)and V-O frame could slower the mobility of Zn^(2+).Furthermore,the thermal instability of ammonium vanadate also limits the use of common carbon coating modification method to solve the problem.Herein,V_(2)CT_(X)MXene was innovatively selected as a bifunctional source to in-situ derivatized(NH_(4))_(2)V_(8)O_(20)·x H_(2)O with amorphous carbon-coated(NHVO@C)via one-step hydrothermal method in relatively moderate temperature.The amorphous carbon shell derived from the V_(2)CT_(X)MXene as a conductive framework to effectively improve the diffusion kinetics of Zn^(2+)and the robust carbon skeleton could alleviate the ammonium dissolution during long-term cycling.As a result,zinc ion batteries using NHVO@C as cathode exhibit superior electrochemical performance.Moreover,the assembled foldable or high loading(10.2 mg/cm^(2))soft-packed ZIBs further demonstrates its practical application.This study provided new insights into the development of the carbon cladding process for thermally unstable materials in moderate temperatures.
基金supported by the National Natural Science Foundation of China(U21A2033)the Fundamental Research Funds for the Central Universities(2652022103).
文摘Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not yet fully understood.In this study,the V(V)reduction mechanisms with concomitant V isotope fractionation by the Gram-positive bacterium Bacillus subtilis(B.subtilis)and the Gramnegative bacterium Thauera humireducens(T.humireducens)were investigated.Both strains could effectively reduce V(V),removing(90.5%±1.6%)and(93.0%±1.8%)of V(V)respectively from an initial concentration of 50 mg L^(-1) during a 10-day incubation period.V(V)was bioreduced to insoluble vanadium(IV),which was distributed both inside and outside the cells.Electron transfer via cytochrome C,nicotinamide adenine dinucleotide,and glutathione played critical roles in V(V)reduction.Metabolomic analysis showed that differentially enriched metabolites(quinone,biotin,and riboflavin)mediated electron transfer in both strains.The aqueous V in the remaining solution became isotopically heavier as V(V)bioreduction proceeded.The obtained V isotope composition dynamics followed a Rayleigh fractionation model,and the isotope enrichment factor(e)was(–0.54‰±0.04‰)for B.subtilis and(–0.32‰±0.03‰)for T.humireducens,with an insignificant difference.This study provides molecular insights into electron transfer for V(V)bioreduction and reveals V isotope fractionation during this bioprocess,which is helpful for understanding V biogeochemistry and developing novel strategies for V remediation.
文摘Elemental doping of BiVO_(4) crystal lattices effectively enhances carrier separation,thereby facilitating efficient photoelectrochemical water splitting.However,the positive effect of elementally induced lattice distortions on hole extraction has been neglected.Herein,the crystal lattice of BiVO_(4) is distorted by doping with an inexpensive Cs metal;then,CoFe_(2)O_(4) is used as an efficient hole-extraction layer to further modify the surface of the doped photoanode.Benefiting from the above design,the newly prepared CoFe_(2)O_(4)-Cs-BiVO_(4) photoanode achieved a photocurrent density of 5.66 mA cm^(–2) at 1.23 V vs.a reversible hydrogen electrode,indicating a 3.9-fold improvement in photocurrent density.Detailed physicochemical characterization and density functional theory calculations showed that the lattice distortion induced by Cs doping promoted the directional migration of BiVO_(4) bulk-phase holes to the CoFe_(2)O_(4) layer.Additionally,the coupled CoFe_(2)O_(4) can be used as a hole extraction layer to further enhance the interfacial migration of carriers.The synergistic effect of the two effectively promotes the directional migration of photogenerated carriers from the BiVO_(4) bulk phase to the active sites of the oxygen evolution reaction,thereby effectively inhibiting carrier recombination.This study revealed the positive effect of the dual-hole extraction strategy on solar energy conversion,thereby opening new avenues for the rational design of photoanodes.
基金Science Fund for Outstanding Young Scholars of Hunan Province,Grant/Award Number:2023JJ20064National Natural Science Foundation of China,Grant/Award Number:12004057+1 种基金Graduate Research and Innovation Foundation of Chongqing,Grant/Award Number:CYB23026Natural Science Foundation of Chongqing Municipality,Grant/Award Number:CSTB2022NSCQ-MSX1183。
文摘Layered vanadates are ideal energy storage materials due to their multielectron redox reactions and excellent cation storage capacity.However,their practical application still faces challenges,such as slow reaction kinetics and poor structural stability.In this study,we synthesized[Me_(2)NH_(2)]V_(3)O_(7)(MNVO),a layered vanadate with expended layer spacing and enhanced pH resistance,using a one-step simple hydrothermal gram-scale method.Experimental analyses and density functional theory(DFT)calculations revealed supportive ionic and hydrogen bonding interactions between the thin-layered[Me_(2)NH_(2)]+cation and[V_(3)O_(7)]-anion layers,clarifying the energy storage mechanism of the H^(+)/Zn^(2+)co-insertion.The synergistic effect of these bonds and oxygen vacancies increased the electronic conductivity and significantly reduced the diffusion energy barrier of the insertion ions,thereby improving the rate capability of the material.In an acidic electrolyte,aqueous zinc-ion batteries employing MNVO as the cathode exhibited a high specific capacity of 433 mAh g^(-1)at 0.1 A g^(-1).The prepared electrodes exhibited a maximum specific capacity of 237 mAh g^(-1)at 5 A g^(-1)and maintained a capacity retention of 83.5%after 10,000 cycles.This work introduces a novel approach for advancing layered cathodes,paving the way for their practical application in energy storage devices.
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(51974369)the Postgraduate Research Innovation Project of Central South University,China(2019zzts244).
文摘The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.
基金Project(51274242)supported by the National Natural Science Foundation of ChinaProject(2015CX001)supported by the Innovation-driven Plan of Central South University,China
文摘A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium chromate from CVR in sodium bicarbonate solution.Results indicate that the stability of calcium vanadate and calcium chromate depends on pH and[HCO3?].CaV2O6?4H2O transforms into CaV2O6?4H2O,CaV2O6?2H2O,CaV2O6,Ca2V2O7?2H2O,and Ca5(VO4)3(OH)when pH increases from 7.51 to 12.32.Increasing pH and reducing CVR dosage improve the vanadate extraction rate,and high V2O5 and Na2Cr2O7?2H2O extraction rates are achieved in dilute NaHCO3 solution.Moreover,addition of NaOH positively contributes to the recovery of vanadate and chromate from CVR.Over 95%V2O5 and Na2Cr2O7?2H2O in CVR can be extracted from 60 g/L NaHCO3 and 30 g/L NaOH solutions at 90°C for 2 h.In order to reduce the hazardous residue containing chromate after recovery of CVR,calcium circulation is presented.Results show that more than 60%lime can be saved with fresh residue addition to remove vanadate from sodium chromate solution due to the active CaCO3.Moreover,no lime is required in removal of vanadate when the roasting residue is added.Therefore,a novel process is developed for utilization of CVR.
文摘The number of papers about decavanadate has doubled in the past decade. In the present review, new insights into decavanadate biochemistry, cell biology, and antidiabetic and antitumor activities are described. Decameric vanadate species (V10) clearly differs from monomeric vanadate (V1), and affects differently calcium pumps, and structure and function of myosin and actin. Only decavanadate inhibits calcium accumulation by calcium pump ATPase, and strongly inhibits actomyosin ATPase activity (IC50 = 1.4 μmol/L, V10), whereas no such ef- fects are detected with V1 up to 150 μmol/L; prevents actin polymerization (IC50 of 68 μmol/L, whereas no effects detected with up to 2 mmol/L V1); and interacts with actin in a way that induces cysteine oxidation and vanadate reduction to vanadyl. Moreover, in vivo decavanadate toxicity studies have revealed that acute exposure to polyoxovanadate induces different changes in antioxidant enzymes and oxidative stress parameters, in comparison with vanadate. In vitro studies have clearly demonstrated that mitochondrial oxygen consumption is strongly affected by decavanadate (IC50, 0.1 μmol/L); perhaps the most relevant biological effect. Finally, decavanadate (100 μmol/L) increases rat adipocyte glucose accumulation more potently than several vanadium complexes. Preliminary studies sug- gest that decavanadate does not have similar effects in human adipocytes. Although decavanadate can be a useful biochemical tool, further studies must be carried out before it can be conf irmed that decavanadate and its complexes can be used as anticancer or antidiabetic agents.
基金Projects(21176263,21175155)supported by the National Natural Science Foundation of China
文摘Mg/Al-CO3 layered double hydroxide （LDH2） with Mg（II）：Al（III） molar ratio of 2：1 was synthesized by co-precipitation method and its calcined product Mg2Al-CLDH（CLDH2） was prepared by heating Mg2Al-LDH at 773 K for 6 h. Removal of vanadate anion （ 3-4VO ） from aqueous solution on CLDH2 was studied. Batch studies were carried out to address various experimental parameters such as Mg/Al molar ratio, adsorbent dosage, initial concentration of solution, contact time and temperature. Vanadate was removed effectively at the optimized experimental conditions. The adsorption kinetics data fitted the pseudo-first-order model. Isotherms for adsorption vanadate by CLDH2 at different solution temperatures were well described using the Langmuir and Freundlich equations, and the isotherm parameters were calculated using linear regression analysis. The adsorption data fitted the langmuir model with good values of the correlation coefficient （R2〉0.999）. The negative value ofΔGΘand the positive value ofΔHΘindicate that the adsorption processes are spontaneous endothermic in nature. The mechanism of adsorption suggests that the surface adsorption is the main process.
基金supported by National Natural Science Foundation of China(Nos.51972346,51932011,51802356,and 51872334)Innovation-Driven Project of Central South University(No.2018CX004).
文摘Rechargeable aqueous zinc-ion batteries(AZIBs)have their unique advantages of cost efficiency,high safety,and environmental friendliness.However,challenges facing the cathode materials include whether they can remain chemically stable in aqueous electrolyte and provide a robust structure for the storage of Zn2+.Here,we report on H11Al2V6O23.2@graphene(HAVO@G)with exceptionally large layer spacing of(001)plane(13.36?).The graphene-wrapped structure can keep the structure stable during discharge/charge process,thereby promoting the inhibition of the dissolution of elements in the aqueous electrolyte.While used as cathode for AZIBs,HAVO@G electrode delivers ideal rate performance(reversible capacity of 305.4,276.6,230.0,201.7,180.6 mAh g?1 at current densities between 1 and 10 A g?1).Remarkably,the electrode exhibits excellent and stable cycling stability even at a high loading mass of^15.7 mg cm?2,with an ideal reversible capacity of 131.7 mAh g?1 after 400 cycles at 2 A g?1.
基金supported by the National Natural Science Foundation of China (No. 20973017, 21077007)the Creative Research Foundation of Beijing University of Technology (No. 00500054R4003, 005000543111501)+2 种基金the HiTech Research and Development Program (863)of China (No. 2009AA063201)the Funding Projectfor Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (No. PHR200907105, PHR201007105,PHR201107104)the Hong Kong Baptist University (FRG2/09-10/023)
文摘Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100°C with poly（vinyl pyrrolidone） （PVP） and urea （pH = 2） and at 160°C with NaHCO3 （pH = 7 and 8）, respectively. The PVP-derived BiVO4 showed much higher surface areas （5.0-8.4 m2/g） and narrower bandgap energies （2.45-2.49 eV）. The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.
基金This study was financially supported by the National Natural Science Foundation of China(No 21905037)the Doctoral Research Startup Fund of Liaoning Province(No.2020-BS-066)+2 种基金the Doctoral Research Fund of Lanzhou City University(No.LZCU-BS2020-03)the Fundamental Research Funds for the Central Universities(No.3132019328)Q.L.acknowledges the financial support from China Scholarship Council(CSC).
文摘Aqueous rechargeable zinc-ion battery(ZIB)is considered to be a potential energy storage system for large-scale applications due to its environmental friendliness,high safety,and low cost.However,it remains challenging to develop suitable cathode materials with high specific capacity and long-term cyclic stability.Herein,we have fabricated freestanding Sr0.19V2O51.3H2O/carbon nanotubes(SrVO/CNTs)composite films with different mass ratios by incorporating SrVO into CNTs network.The synthesized SrVO possesses a large interlayer spacing of 1.31 nm,which facilitates Zn(2+)diffusion.Furthermore,the SrVO/CNTs composite film with conductive network structure promotes electron transfer and ensures good contact between SrVO and CNTs during the long-term cycling process.As a result,the battery based on the SrVO/CNTs composite cathode with a mass ratio of 7:3 delivers a specific capacity of 326 mAh·g^(-1)at 0.1 A·g^(-1)and 145 mAh·g^(-1)at 5 A·g^(-1),demonstrating a high capacity and excellent rate capability.Remarkably,the assembled ZIB shows good capacity retention of 91%even after ultra-long cycling for 7500 cycles at a high current rate of 5 Ag^(-1).More importantly,the battery also delivers a high energy density and power density,as 290 Wh·kg^(-1)at 125 W·kg^(-1)(0.1 A·g^(-1)),or 115 Wh·kg^(-1)at 6078 W·kg^(-1)(5 Ag^(-1)).The results demonstrate that the SrVO/CNTs composite is a promising cathode toward large-scale energy storage applications.
基金This work was supported by the National Science Foundation(CBET-1803256)National Natural Science Foundation of China(Grant No.51772267)+3 种基金the National Key R&D Program of China(Grant No.2016YFB0401501)the Key R&D Program of Zhejiang Province(Grant No.2020C01004)The author acknowledges the financial support from China Scholarship Council(No.201906320198)2019 Zhejiang University Academic Award for Outstanding Doctoral Candidates.
文摘Ammonium vanadate with bronze structure(NH_(4)V_(4)O_(10))is a promising cathode material for zinc-ion batteries due to its high specific capacity and low cost.However,the extraction of NH^(+)_(4) at a high voltage during charge/discharge processes leads to irreversible reaction and structure degradation.In this work,partial NH^(+)_(4) ions were pre-removed from NH_(4)V_(4)O_(10) through heat treatment;NH_(4)V_(4)O_(10) nanosheets were directly grown on carbon cloth through hydrothermal method.Defi-cient NH_(4)V_(4)O_(10)(denoted as NVO),with enlarged interlayer spacing,facilitated fast zinc ions transport and high storage capacity and ensured the highly reversible electrochemical reaction and the good stability of layered structure.The NVO nanosheets delivered a high specific capac-ity of 457 mAh g^(−1) at a current density of 100 mA g^(−1) and a capacity retention of 81%over 1000 cycles at 2 A g^(−1).The initial Coulombic efficiency of NVO could reach up to 97%compared to 85%of NH_(4)V_(4)O_(10) and maintain almost 100%during cycling,indicating the high reaction reversibility in NVO electrode.
基金the financial support from the National Natural Science Foundation of China(No.51902165)the Natural Science Foundation of Jiangsu Province(No.BK20170917)+2 种基金the Scientific Research Foundation for High-Level Talents of Nanjing Forestry University(No.GXL2016023)the Program of High-Level Talents in Six Industries of Jiangsu Province(No.XCL-040)the Jiangsu Specially-Appointed Professor Program。
文摘It is urgent to develop high-performance cathode materials for the emerging aqueous zinc-ion batteries with a facile strategy and optimize the related components.Herein,a Ca0.23V2O5·0.95 H2O nanobelt cathode material with a rather large interlayer spacing of 13.0 A is prepared via a one-step hydrothermal approach.The battery with this cathode material and 3 M Zn(CF3SO3)2 electrolyte displays high specific capacity(355.2 mAh g^(-1)at 0.2 A g^(-1)),great rate capability(240.8 mAh g^(-1)at 5 A g^(-1)),and excellent cyclability(97.7%capacity retention over 2000 cycles).Such superior performances are ascribed to fast electrochemical kinetics,outstanding electrode/electrolyte interface stability,and nearly dendrite-free characteristic.Instead,when ZnSO4 or Zn(ClO4)2 is used to replace Zn(CF3SO3)2,the electrochemical performances become much inferior,due to the slow electrochemical kinetics,inhomogeneous Zn stripping/plating process,and the formation of large dendrites and byproducts.This work not only discloses a high-performance cathode material for aqueous zinc-ion batteries but also offers a reference for the choice of electrolyte salt.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51802356, 51872334 and 51572299)Innovation-Driven Project of Central South University (No. 2018CX004)
文摘Due to the intrinsic advantages of nontoxicity, low-cost, and abundant resource of metallic zinc, aqueous zinc-ion batteries (ZIBs) have attracted universal interest [1,2]. Tremendous cathode materials have been exploited in aqueous ZIBs, such as manganese-based materials [3-11], Co-based materials [12,13] and vanadium-based materials [14-21].
